Fleece covering to warm up beds?

[RhysParticipant]

Charles

I’ve just given my no-dig beds (18 months now no-dig() their first gentle hoe/rake of the year and was pleasantly surprised that a certain amount of fine tilth can already be generated in February.

My hope is that it will be possible to try sowing parsnip and carrots earlier this year, to try and give them the maximum length of growing season (particularly for the parsnips).

In that regard, I was thinking of covering the relevant bed with fleece in the hope that the sun’s rays will warm the top soil up significantly in the next few weeks.

Does this have a significant effect in your experience or will it be better to wait until the March full moon (this year toward the end of the month) before sowing parsnips?? I don’t think I will sow carrots before then anyway, quite possibly waiting until the April full moon for main crop…..

[charlesModerator]

Good question and two things stand out for me:
1 Sowing parsnips in February does not necessarily mean a bigger harvest, for example older parsnips suffer more canker, though mostly on heavy soils, less on light ones.
2 For the small benefit of pre-covering with fleece, I am unconvinced that its worthwhile. Sure lay it over sowings, and they are germinating for a long time, so the warming effect coincides with that. I favour sowing mid March, roughly (vis weather, moon) and laying fleece over sowings, not before.

[RhysParticipant]

Fair enough: thanks for the honest advice!

[compostpopeParticipant]

Covering beds with black plastic to warm the soil prior to sowing was recomended by “Gardener’s Question Time” on Radio 4 within the last few years, though I have never tried it myself…..

[AndyParticipant]

I don’t know if there is a special knack to using black plastic for warming the soil, but as most magazines and garden “experts”mention it regularly I tried it about 3 years ago in early spring .I could not detect any benefit at all.

[charlesModerator]

I agree Andy.
Soil warms and cools very fast, particularly in the spring. I have never seen evidence that this plastic trick makes a difference because of the warmth disappearing before its made a difference to growth.
Probably it has more benefit from keeping rain off, as long as the soil is fully moist before plastic is laid,
Still marginal in my opinion. Dark compost on the surface is good!

[TParticipant]

I did an experiment with some children with clear plastic, black plastic and with cardboard, and we found no difference really compared to uncovered ground (just 1C). However, if you can put a cloche over the area, I suspect that would have a bigger effect, judging by weed growth.

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